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近年来,我国利用苏云金杆菌(简称Bt)制剂防治农林害虫的面积逐年扩大,防治的虫种也不断增加,万亩以上应用防治效果达75％以上。据国外报道:长期使用Bt制剂,对菜田蚜虫,果园害螨均比化学农药防效好。对棉田、蔬菜的天敌有什么影响呢?近年我们进行了调查研究,现总结如下: 1、自1987年开始连续三年对棉田捕食性天敌的消长调查表明,用2000倍敌杀死对天敌有很大杀伤,破坏了棉田的生态平衡,导致伏蚜猖獗。而使用200倍Bt制剂对天敌有良好的保护作用。防治后2天,使用Bt制剂比敌杀死天敌总量高3倍左右,与不使药的基本一致。防治后5天,化防田天敌比生防田仍低50％。以三年均值比较两田防治前后天敌的变化,防治后比防治前,化防田蜘蛛减少72％,食虫蝽减少91％,瓢虫减少100％,其它天敌减少
In recent years, the use of Bacillus thuringiensis (Bt) preparations for the prevention and control of agricultural and forestry pests expanded year by year, prevention and control of insect species also continue to increase, more than mu of application of prevention and control of more than 75%. According to foreign reports: long-term use of Bt preparations, aphids on vegetable fields, orchards pest mites are better than chemical pesticides. In recent years, we conducted a survey and research, are summarized as follows: 1, since 1987 for three consecutive years of cotton consumption predation of natural enemies survey showed that with 2000 times the enemy killed on natural enemies have Great destruction, destroyed the ecological balance of cotton fields, leading to the presence of aphids. The use of 200 times Bt preparations on natural enemies have a good protective effect. Two days after the control, the use of Bt preparations than the enemy to kill the total amount of natural enemies about 3 times higher, and basically the same drug. Five days after the prevention and control, natural enemies of the anti-field are still 50% lower than those of the anti-agricultural fields. Compared with the control before and after the control, the three-year average compares the changes of natural enemies in both fields before and after the prevention and treatment, the prevention and cure of the field spiders decreased by 72%, the bug insects reduced by 91%, ladybug reduced by 100% and other natural enemies decreased